Much of our lives are spent in groups with other people: we form groups to socialise, earn money, play sport, make music, even to change the world. But although groups are diverse, many of the psychological processes involved are remarkably similar.

Here are 10 insightful studies that give a flavour of what has been discovered about the dynamics of group psychology.
1. Groups can arise from almost nothing

The desire to form and join social groups is extremely powerful and built into our nature. Amongst other things groups give us a most valuable gift, our social identity, which contribute to our sense of who we are.

Just how readily people form and join groups is demonstrated by Tajfel et al. (1971) in the so-called ‘minimal groups paradigm’. In their study boys who were strangers to each other were given only the slightest hint that they they were being split into two groups. Even without knowing or seeing who else was in their group they favoured members of their own group over the others. Group behaviour, then, can arise from almost nothing.
2. Initiation rites improve group evaluations

Existing groups don’t let others join for free: the cost is sometimes monetary, sometimes intellectual, sometimes physical—but usually there is an initiation rite, even if it’s well disguised.

Aronson and Mills (1959) tested the effect of initiation rites by making one group of women read passages from sexually explicit novels. Afterwards they rated the group they had joined much more positively than those who hadn’t had to undergo the humiliating initiation. So, not only do groups want to test you, but they want you to value your membership.
3. Groups breed conformity

After joining a group and being initiated, we have to get a feel for the group norms, the rules of behaviour in that group. Group norms can be extremely powerful, bending our behaviours in ways we would never expect.

One of the most famous experiments showing how easily we conform to unwritten group rules was conducted by Asch (1951). He had participants sit amongst a group of other people, judging the length of a line. The trick was that all the other members of the group were confederates of the experimenter who had been told to lie about which line was longer. Incredibly 76% of participants denied the evidence from their own senses at least once, just to conform with the group. Afterwards people made up all kinds of excuses for their behaviour. Most popular was a variation on: “that many people can’t be wrong”. Oh yes they can.
4. Learn the ropes or be ostracised

Group norms are extremely pervasive: this becomes all the more obvious when we start breaking them. Garfinkel (1967) had adolescents return to their families and behave totally out of character, i.e. speaking only when spoken to, being polite, acting formally—but only for 15 minutes at a time. Rather than being delighted their parents were shocked and angry, accusing their children of being selfish and rude. Break the group’s rules and you’ll know about it soon enough.
5. You become your job

Although groups have norms—rules that apply to everyone in the group—people have roles within groups and corresponding rules that apply to just their position. The most well-known demonstrations of the power of roles is the Stanford Prison Experiment.

Psychologists put young men into a simulated prison environment, making some prisoners and others guards (Zimbardo, 1972). After only 6 of its planned 14 days the experiment had to be stopped because participants conformed all too well to their roles as submissive prisoners or domineering guards. Some were emotionally disturbed by the experience. Even the experimenters were succumbing to their ‘roles’ as prison superintendents before the plug was pulled on the whole experiment.
6. Leaders gain trust by conforming

A high-profile, high-status role in any group is that of its leader, but where do leaders come from? In some groups, they are appointed or imposed from outside, but in many groups leaders emerge slowly and subtly from the ranks.

A study that has much to teach was carried out by Merei (1949) who observed children at a Hungarian nursery school. He noticed that successful leaders were those who initially fitted in with the group then slowly began to suggest new activities adapted from the old. Children didn’t follow potential leaders who jumped straight in with new ideas. Leaders first conform, then only later, when trust has been gained, can they be confident that others will follow. This has been confirmed in later studies (with grown-ups!).
7. Groups can improve performance…

The mere presence of others can make us perform better. Social psychology pioneer Norman Triplett noticed that racing cyclists with a pacemaker covered each mile about 5 seconds quicker than those without (Triplett, 1898). Later research found this wasn’t all about the effects of competition. The presence of other people seems to facilitate our own performance, but more so when the task is relatively separate to others and can be judged on its own merits.
8. …but people will loaf

In other circumstances, though, people in groups demonstrate a tremendous capacity for loafing. Another social psychology pioneer, Max Ringelmann, found in the 1890s that participants in a tug ‘o war only put in half as much effort when they were in a team of 8 than when they were on their own. It seems that when hiding in the group is easy, for example when tasks are additive and each person’s contribution is difficult to judge, people will slack off to an impressive degree.
9. The grapevine is 80% accurate

Intelligence, rumour, gossip and tittle-tattle is the lifeblood of many groups. It travels at a tremendous pace in big organisations because people love a good bit of gossip, but what are ‘they’ talking about and can you believe what ‘they’ say?

Simmons (1985) analysed workplace communication and found that about 80% of the time people are talking about work and a surprising 80% of the information was accurate. Other studies have come up with a similar figure, suggesting that while details are inevitably lost along the way, the grapevine is mostly accurate.
10. Groups breed competition

While co-operation within group members is generally not so much of a problem, co-operation between groups can be hellish. People may be individually co-operative, but once put in a ‘them-and-us’ situation, rapidly become remarkably adversarial.

Insko et al. (2001) had participants playing a classic game called ‘the prisoner’s dilemma’ which they used to measure competitiveness. When on their own people were competitive 37% of the time but when they were in a group of three this increased to 54%. People easily become suspicious of other groups, reasoning that while their individual members may be ‘alright’, the group as a whole cannot be trusted.

Thanks for contributing this article! Apparently, my watershed group needs a “rite of initiation” if we want more appreciative, dedicated members. We probably can’t get away with the sexually explicit novel reading so I’ll have to come up with something else.